2020 Fiscal Year Final Research Report
Breakthrough toward "second-generation" grain boundary engineering
| Project/Area Number |
16H06366
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Material processing/Microstructural control engineering
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| Research Institution | Kumamoto University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
小林 重昭 足利大学, 工学部, 教授 (00323931)
大村 孝仁 国立研究開発法人物質・材料研究機構, 構造材料研究拠点, 副拠点長 (40343884)
井 誠一郎 国立研究開発法人物質・材料研究機構, 構造材料研究拠点, 主幹研究員 (60435146)
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| Project Period (FY) |
2016-05-31 – 2021-03-31
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| Keywords | 結晶・組織制御 / 粒界 / 粒界工学 / 双結晶 / ナノインデンテーション / TEMその場変形 |
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| Outline of Final Research Achievements |
The motivation of this project was to achieve a breakthrough toward second-generation grain boundary engineering (GBE). For this purpose, we dealt with two major issues: (1) comprehensive understanding the mechanical response due to the interaction of grain boundary (GB) and dislocations, and (2) development of guiding principle for GB control of materials with high stacking fault energy. We have found with nanoindentation tests and TEM in-situ straining experiments for orientation-controlled bicrystals that GBs act as preferential sites for nucleation of dislocations, and succeeded in quantitative evaluation of the critical stresses for dislocation nucleation and for slip transmission across the GBs. Those critical stresses were found to depend on the GB structure. As for the issue (2), we developed the processing routes for introducing high frequency of low-energy GBs and found that the newly developed GBE achieved enhanced bulk properties like fatigue and corrosion resistance.
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| Free Research Field |
材料工学、材料加工・組織制御工学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究は、伝統的な双結晶実験を踏襲しながら、ナノインデンテーション試験や電子顕微鏡と組み合わせたその場観察・解析技術、第一原理計算や分子動力学シミュレーション等の計算科学を活用した最新の実験手法を用いて、既存の理解を見直すことにより粒界研究の深化を図った。体系的に普遍的学理を得ることを目的として行ってきた本研究の成果は高い学術的意義がある。さらに、積層欠陥エネルギーの高い材料に対する粒界制御法を確立したことは、広範な材料に対して粒界工学の応用の道を開いた。希少元素に頼らない新しい材料開発技術として、元素戦略上も社会的波及効果は大きい。
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